[Extensions] Add an access check before executing native code in the renderer

extensions/renderer/user_gestures_native_handler.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/user_gestures_native_handler.h"
 
 #include "base/bind.h"
 #include "extensions/renderer/script_context.h"
 #include "third_party/WebKit/public/web/WebScopedUserGesture.h"
 #include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
 
 namespace extensions {
 
 UserGesturesNativeHandler::UserGesturesNativeHandler(ScriptContext* context)
     : ObjectBackedNativeHandler(context) {
   RouteFunction("IsProcessingUserGesture",
+                "test",

[Devlin, 2016/03/30 22:02:28]

Ideally, we'd be able to attribute all the native handlers to a particular API
in order to perform this check.  We can go through and update them piecemeal if
this lgty.

                 base::Bind(&UserGesturesNativeHandler::IsProcessingUserGesture,
                            base::Unretained(this)));
   RouteFunction("RunWithUserGesture",
+                "test",
                 base::Bind(&UserGesturesNativeHandler::RunWithUserGesture,
                            base::Unretained(this)));
   RouteFunction("RunWithoutUserGesture",
+                "test",
                 base::Bind(&UserGesturesNativeHandler::RunWithoutUserGesture,
                            base::Unretained(this)));
 }
 
 void UserGesturesNativeHandler::IsProcessingUserGesture(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   args.GetReturnValue().Set(v8::Boolean::New(
       args.GetIsolate(),
       blink::WebUserGestureIndicator::isProcessingUserGesture()));
 }
@@ skipping 10 matching lines @@
 void UserGesturesNativeHandler::RunWithoutUserGesture(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   blink::WebUserGestureIndicator::consumeUserGesture();
   CHECK_EQ(args.Length(), 1);
   CHECK(args[0]->IsFunction());
   v8::Local<v8::Value> no_args;
   context()->CallFunction(v8::Local<v8::Function>::Cast(args[0]), 0, &no_args);
 }
 
 }  // namespace extensions